ASSIGNMENT 1, ASSIGNMENTS, Notes, Research & Reflection

Post-mortem/ reflections on Assignment 1

Here are my views on my Assignment 1 attempt, a day after closing and sending off the Sibelius file to OCA.   I took the invitation implied in earlier projects to choose a piece freely rather than following the much more narrow (updated?) instructions to continue an existing start of a work.  Mainly, I wanted to explore some ideas from the minimalist movement about phasing, and to write something that was loosely constrained by a natural process, the timing and amplitude of the tides.


The idea is so far as I know original.

I did, as suggested, pick an unconventional time signature.  25/16 seems to be a Bulgarian dance  rhythm ‘sedi donka’ as 7 + 7 +11.  My usual pattern of six crotchets plus a ‘skip’ semiquaver instead tries to set up the idea more clearly of phasing.  I believe, with the help of Sibelius, that I have notated this as clearly and practically as I can, for example showing the beats in the bar immediately before one of the periodic gong entries.

The overall shape of loud/excited and soft/contemplative followed quite strictly the design in my earlier blog:

The ending is exciting

The shifting of the claves ‘high tide’ against the triangle ‘lunar 25 hour day’ is audible and quite hypnotic in the quieter music.

The design, to bring the two back into sync on the last note, was technically followed through.

I experimented with a very wide range of cross-rhythms.

I believe the percussion parts would be technically playable, though conducting this would be tough.  The triangle semiquaver at the end of every bar does at least act as a flag or anchor for the players to know when to start the next bar.  Having two side drummers is a practical decision to reduce fatigue, and add interest since very often one imitates the other, though often at a different dynamic


For an unpitched percussion piece with no change in speed or time signature, or completely contrasting section of different instruments, this first serious attempt, at getting on for 10 minutes is too long to easily sustain attention if you are listening to it as a pure performance piece without also following the concept.  That’s a problem with a lot of twentieth century music though e.g. Boulez ‘Le Marteau sans Maitre’ or Stockhausen ‘Cosmic Pulses’, I think around 40 minutes each.  However Varese ‘Ionisation’ on 7 minutes is more interesting as  a pure untuned percussion piece, if you forgive the tuning of the sirens!  Oh and I think I hear the bongos playing a triad at one point….

There are too many bars in my piece with side drum semiquavers, at least when I have listened to this multiple times.  Perhaps with the anticipation of fresh listening they could be said to create suspense.  But really they reflect me running out of time.

Fundamentally this is over-ambitious for a first attempt.  However I now know more about what it takes to score something on this scale, and the need for more than one basic concept to create variety.


Useful learning experience.  I know more about some of the less classical untuned percussion; I particularly like the sound of temple blocks but used this in an earlier project so wanted to try out something different.  In fact I am still curious to hear again what this ‘Welcome to Ceredigion’ sounds like.  With a lot more time, I am sure I could improve the piece.  So an Opus zero then not an Opus 1 !

Looking forwards to being allowed to use PITCH and all the things that brings with intervals, harmony and melody.

Other notes

One influence in making so prominent a side drum part was perhaps the side drum solo ‘against the orchestra’ in the first movement of Neilsen’s fifth symphony.

Reich really pioneered ‘Phasing’ but when you analyse  a number of his works, the basic rhythm within which the phasing takes place is a regular one.  So for example in ‘Music for Pieces of Wood’, the only one I know apart from Clapping without tuned pitch, the repeating cell is either 6 beats, 4 or 3 beats right at at the end.  I had to see that rather than hear it, so my initial idea of hearing a 25 versus 24 cross-rhythm is clearly just too demanding on the aural short term memory.  The following nice visualisation of Reich’s own phasing for claves (at different pitches) makes clear to the eye, and then to the ear what is going on.  I will think about that joint appreciation through both eyes and ears for some future work e.g. using stereo or even binaural synthesis.

A footnote on the ‘gong ageng’: this is the largest of the Javanese gamelan instruments and traditionally used to start and end a sequence

If not available, I imagine a tam tam would substitute, but its resonance may continue for rather long unless stopped, which can seem abrupt.


Assignment 1 wav file and pdf

This is my assignment on untuned percussion.  It’s based on the ideas of phasing and tide tables.  The title ‘Welcome to Ceredigion’ was on the tide table for summer 2014 which I drew on for the timing and dynamics.  More commentary on the composition process tomorrow.  It’s something of an experiment:

Welcome to Ceredigion sync and dyn 2015_5 – Full Score


The time signature 25/16 relates to 12 and half hours as a close approximation to the time between high tides or between low tides.  A half hour is a semiquaver and the shortest unit in the music is a demisemiquaver so that the tides are rounded to the nearest quarter hour.  The actual tides follow a more complex rhythm and advance slowly on this period.  The turn of the tide is marked by a strike of the claves, and normal ‘clock’ (or earth) time is marked by a wood block every two hours, which corresponds to four semiquavers in the score.  This is on the main beat (6×4 + 1)/16 only once every four bars.  The perception of the beat shifts accordingly; sometimes I use accents to reinforce the written bar and sometimes to undermine it, for example using a 5 x 5 division of the bar in the bass drum.  A whip crash marks the point of the highest ‘spring’ tide about once every 14 days, typically near full moon and new moon when the moon pulls the tides along the same axis as the sun.  Over the composition as a whole, there are six such high points when the music is loud and busy.  In between these the steady pulse of half hours on the two side drums decays and at the time of greatest slack, disappears altogether.  A triangle strike, however, regularly marks the 25th semiquaver.


Back in action – natural cycle as basis for percussion assignment


It’s been a while but I’ve now sorted times and amplitudes for three months’ tides at Aberystwyth. If I use the height of the low tide, the lower curve, as a guide to excitement/volume then the piece will start at modest volume, end on a crescendo and have three main peaks:


Aberystwyth tide wave form

Next step is to work out the exact ‘phasing’ of these low tides – further apart as they get lower, I believe.

The graph below is the result of alignment to a 25-beat norm of 12 and a half hours between low tides, selecting start (3 tides skipped) and end to complete at zero but with a phase advancement of a single 25-beat bar through the piece as a whole.  The blue bars are the beat phasing and the red bars which will be interpreted as ‘excitement’/volume are 25 minus ten times low tide height in metres.  This a proxy for high tide height and has the result that amplitude is greatest where the tides are accelerating – i.e. the phase is advancing (getting earlier faster)

An additional 24-beat rhythm within the 25-pulse metre will correspond to half-hours on the sidereal clock and starts with a change in the same direction as the tides, but then diverges.  At the end, 175 half-days, this rhythm will also return to the bar line.

Phasing of low tides relative to 12 and a half hour norm


The original file with tide tables is attached here for reference as an Excel 2007 set of pages:

Aberystwyth low tides quantised inverted V3

ASSIGNMENT 1, Listening log, Research & Reflection

Steve Reich Drumming – based on psychological illusions?

Strange experience today – had Steve Reich’s long, hypnotising ‘Drumming’ playing in a room that I was dipping in and out of.  While in the room, I could rarely hear the shifting rhythms but every time I came back in after a short absence I heard a different main beat.  Is that just because the music moves slowly, or am I locking into a particular pulse as you do when looking at a view of a Necker cube?  But for other optical illusions the retina at a low level becomes desensitised, ‘tired’ of a particular location or colour which is why you see read afterimages after looking at a green spot.  Can this also happen in acoustics and music, I wonder?

ASSIGNMENT 1, Planning, Research & Reflection

Assignment 1 thinking and reflection

Listened to Steve Reich’s Music for Pieces of wood (which requires tuned claves).  His style is to set up a rhythmic pattern and then subtly undermine it with a cross-rhythm.   If the asynchronised rhythms start to converge again this is like ‘entrainment’ in classical mechanics theory of oscillators – why two mechanical clocks on the same wall with the same pendulum length will converge to beat in time:

This inspired me to think about planning a percussion piece with the bar (for notational simplicity, a pair of bars) representing the average interval between high tides; the time of high and the low tide represented by wood blocks at two distinct pitches (temple blocks?)  diverging outside and inside the bar.  Depending on temp this needs to be rounded to the nearest demi- or semiquaver.  The tidal range varies with the lunar cycle and this can set dynamics in the obvious way. The highest and lowest tides (spring tides) have the largest intervals about them.  Assuming also a side drum (or pair of side drums handing over between each other, for practicality), playing at 12 quavers in half a day, and also that the average time between tides is 12.5 hours, then the  basic bar pattern is 12/8 alternating with 13/8, and a Reich-like progressive syncopation is set up as  a day ‘beat’ say on triangle every 24 quavers, returning to synchrony after (2 x (12+13) = 50 bars

Added interest can be from bass drum for waves overspilling the promenade (randomly chosen around ‘spring high tides) and by contrast a suspended cymbal roll around neap tides – e.g. sand blowing in the wind.  A speaker could say the tide height in metres at spring high and low tides – the whole piece ending after some multiple of the lunar month 28 days to say ‘come in number 56’ or 84 – to fit allowed length.  84 lunar days (around three months) would last 168 bars at dotted crotchet = 100 is nearly 7 minutes; a reasonable performance length for the audience to get the hang of the shifting rhythms and not get bored.  For comparison, Steve Reich’s piece is 9 minutes on youtube.

A tide table for three months at Aberystwyth is:

Aberystwyth raw tide tables

The source for this was entitled ‘Discover Ceredigion’ which could be the working title of the piece: